Steam doesn't choose the prices
I know. But the same prices they are dictating elsewhere as well and it's cheaper.
There used to be a time when I was excited for any Steam sale. Now, it doesn't matter. It's always more and just a fad marketing ploy at this point. Publisher's fault, Valve's fault for taking huge percentages, or a combination of the above.
Ex: No Man's Sky - $29.99 Steam. $25.99 GMG.
Far Cry 5: $14.99 Steam. $12.74 GMG.
Dark Souls 3 Deluxe: $21.24 Steam - $18.06 GMG
Sekiro: $38.99 Steam: $34.99 GMG
Shadow of the Tomb Raider Definitive Edition: $23.68 Steam - $20 on GMG.
That's just a few that took 4 seconds to look up. Basically any game on sale on Steam right now is 3-5 dollars cheaper on GMG. Activates on Steam anyway. Downloads from their service, and gives you full steam functionality.
Basically saying Shop around because Steam sales are more expensive for the same game and same activation on GMG, cheaper console physical editions which you can trade in, and people are falling for the hype of a Steam sale.